Conventionally, as means for transporting a workpiece, etc., a fluid pressure cylinder having a piston displaced under operation of supplying pressurized fluid has been used.
For example, Japanese Laid-Open Patent Publication No. 06-235405 discloses a fluid pressure cylinder of this type. The fluid pressure cylinder includes a cylindrical cylinder tube, a cylinder cover provided at one end of the cylinder tube, and a piston provided in a displaceable manner inside the cylinder tube. Further, each of the piston and the cylinder tube has a non-circular shape in cross section perpendicular to the axial line. In the structure, in comparison with the case of using a piston having a circular shape in cross section, the pressure receiving surface area is increased, and the outputted thrust force is increased.
Further, Japanese Laid-Open Patent Publication No. 2011-508127 (PCT) discloses a cylinder apparatus including a piston having a square shape in cross section. The cylinder apparatus includes a cylinder housing also having a square shape in cross section corresponding to the cross sectional shape of the piston. Sealing members are provided through grooves at outer marginal portions of the piston. The sealing members contact inner wall surfaces of the cylinder housing to perform sealing operation.